How to get rid of XSS from a remote page in a frame?

Question

PHP

To simplify the example, I will give the following code

. There is a form on the page:

<form id='send' action='../lib/getpage.php' method='post' target='getpage'><br>
       <input id='url' name='url' type='text' value=''><br>
</form><br>

Which betrays the getpage.php file into a frame:

<iframe id='getpage' name='getpage' src='' class='autoHeight' frameborder='0' scrolling='auto'></iframe><br>

The getpage.php file itself produces the page body:

<?<br>
       $url = $_POST['url'];<br>
       $page = file_get_html($url);<br>
       echo $page;<br>
?><br>

If the deleted page contains XSS code, will it affect my site and if so, how to get rid of it?

Answer 1

and if just cut out all possible xss in $page before output in getpage.php?